The commandment to "be fruitful and multiply" as issued to Adam emanated from the Divine Spirit, the "right" side of the sefirot, whereas the identically worded commandment issued to Noah and his sons after the Deluge was rooted in man's sex drive, derived from the "left" side of the sefirot.

In Noah's generation everyone was considered an idolator and it was reasonable to assume that the children would take after their fathers. Noah, on the other hand, took a more optimistic view of the possible development of the minors. G‑d therefore told him that he could not save any youngsters barring his own.

The Shelah teaches that Noah's spiritual strength was not as great as Abraham's, who had "awakened" himself to recognize and serve his Creator. Noah, on the other hand, relied on G‑d's initiative to be the first step. When the Torah describes Noah as "walking with G‑d", this means after G‑d had inspired him first.

Every time a person violates a commandment he acquires an accuser for himself, a destructive angel. G‑d keeps the accuser in check as long as our sins are minor. Before G‑d had completed judging everyone individually in the generation of the Flood, the collective total of the destructive powers created by man's sins already dominated the earth.